Various kinds of input devices for operating a computing system, for example, a button, key, joystick and touch screen, etc., are being developed and used. The touch screen has a variety of advantages, e.g., ease of operation, miniaturization of products and simplification of the manufacturing process, the most attention is paid to the touch screen.
The touch screen may constitute a touch surface of a touch input device including a touch sensor panel which may be a transparent panel including a touch-sensitive surface. The touch sensor panel is attached to the front side of the touch screen, and then the touch-sensitive surface may cover the touch screen. The touch screen allows a user to operate the computing system by touching the touch screen with his/her finger, etc. Accordingly, the computing system recognizes whether or not the touch has occurred on the touch screen and a touch position on the touch screen and performs arithmetic operations, thereby performing actions according to the user's intention.
Meanwhile, there is a requirement for a device for sensing even the touch pressure for convenience of operation and a research on the device is being conducted. However, in the sensing of the touch pressure, there is a problem that the touch pressure cannot be sensed with a uniform sensitivity on the display surface. Furthermore, due to the difference in the manufacturing process or manufacturing environment, different sensitivities may be shown for each manufactured product. For the purpose of compensating this, therefore, the touch pressure device needs to compensate for the sensitivity.